Prior to the present invention, it has been known to apply marks to a product for inspection and/or identification purposes. However, with the equipment available to a manufacturer of these products to be marked, application of such identification or inspection marks were often difficult to achieve and generally expensive.
Typical marking devices in use at the present time are mechanical and include numerous component parts which are subject to excessive wear. Obviously, such wear adds to the cost of applying a mark to a product due to excessive maintenance requirements.
Further, these prior art marking devices utilize liquid inks which may have a relatively long drying time. Excessive drying time often times will result in the mark being smeared during subsequent handling of the product. In order to overcome this problem, it is more or less the practice to provide drying stations or tunnels. This prior art practice obviously adds to the cost of applying a mark to a product.
To overcome this problem, some manufacturers utilize inks which have a rather rapid drying time. However, these rapid drying inks utilize solvents which can create health and environmental problems.
In many production facilities space for marking devices is limited. Such space limitations create significant difficulty in both installing and maintaining the marking equipment. Another problem associated with the use of marking devices requiring liquid ink is that significant time is involved in start-up and subsequent clean up of the equipment.
Prior art marking devices also include, what is commonly known in the art as, foil leaf printers. Foil leaf printers have the drawback that their is a considerable amount of waste material, i.e., foil. Further, these foil leaf printers are somewhat complex in design and require the use of a relatively high force in order to transfer the mark to the product. Often times such high force results in damage, particularly, to delicate products. The product damage in this manner obviously adds to the cost of manufacturing these products.
Other prior art marking devices include spray or ink jet non-contact printers. These non-contact printers usually produce a lower quality mark and lack opacity on dark colored objects which may be objectionable.
The solvent based inks used in all of the above devices create potentially serious fire hazards and require special handling, shipping and storage.